Yes it is just normal. Me and other people also have this thin black border. I didn't even noticed it until I saw someone else's post here on the forums. There are 2 or 3 different posts that address the same question.
Have a nice day and don't worry about this anymore. I just think that ASUS has made the bezel a bit too wide and that's why we have those 2 black lines in the left and up side of the display.